Med Cezir is the bomb. The staff was very friendly and servicable from the moment we walked in; they speak English well. They are constantly offering complementary tea and assuring that you enjoy your stay. The location is perfect for the more touristy area of Istanbul. Although the commodations aren't lavish, everything is clean.
I would ask if they have any suggestions for cheap secrets because sometimes what they recommend was on the pricy side.
I highly recommend their hotel.

Not only was this hostel under construction, which I only found out after having made the reservation, I still haven't received my initial deposit, even having made a reservation at another hostel. All my communications with this hostel have been sketchy and on unofficial e-mails. Do not reserve here!

I got really mixed vibes from this hostel. The staff seemed friendly, but sometimes I wondered if they were being nice just to get good reviews. Also, being that my room shared a window with the reception desk, it was hard to sleep with the racket of that and the obnoxious people I shared a room with. The free walking tour was nice, but if I were to go back to Sevilla I'd find a place that loans out more generous sheets and has more accessible bathrooms.

The staff was nice, but they charge you for time on the computer and for a lock in your room. The breakfast was fairly limited, and I would recommend that you stay in a room with fewer persons. The hostel is well-located.

This hostel was a mixed experience. The employee treated me like an idiot, and they didn't have any computers for internet access. The location is essentially a dump and the hostel is not all that nice. That said, I got my own six-person room for 2 nights, and they let me store my stuff there free of charge for half a day after I checked out.

The bad thing about this hostel is that they nickel and dime you for things like Internet and a lock on your locker. The top bunk was also quite rickety. The staff was quite nice though and the location is conveniently located and in a good neighborhood.